I've got a small child. I'm pretty sure – was pretty sure – he isn't a Child Genius (Channel 4). Well, he's mine, and his mother's: I think it would be almost genetically impossible. And to begin with he showed no signs of even having a brain. Recently though I've become worried. All he wants to do is read books. Books! From the moment he wakes up to the moment he goes to sleep he's got his nose in one.

OK, so we're talking Noisy Train and Whose Bottom at the moment, but recently he's been eyeing up the ones on the shelves (decoration obviously); the other day he pulled Richard Dawkins down. I've tried to discourage him, put him in front of the telly, bought him toys with batteries to lower his attention span, I'm saving up for iPads and Wiis and everything. And he IS going to be a footballer. So come out and practise, kick a ball around? "Book," he says.

Where is this leading? Will he end up like Shrinidhi here? Ten years old, Shrinidhi is already a world Scrabble champion, and she's written four novels (three more than Emily Brontë did ... I think). She enjoys sniffing books – little pervert. Her ambition is to be an etymologist and a consultant for putting words into dictionaries. What kind of ambition is that? Now her mother has entered her into the Child Genius of the Year competition organised by Mensa as she'd like Shrinidhi to meet other gifted children …

Such as little engineering enthusiast Hugo, also 10, who likes trains. He has the entire rail network committed to memory and goes into spasms of joy on spotting a rare locomotive, or a favourite waterworks. Hugo's my favourite, he's really funny and self aware, and a little a bit ironic, as well as being a genius. When he says, "They are actually my favourite waterworks," he does so knowingly and provocatively.

They're all nice actually – Shrinidhi and Hugo, eight-year-old chess superstar Josh and 10-year-old all-rounder Longyin who lives in a house called Wits End in Devon. Of course their parents are at least as interesting as they are, and this is just as much about them. They have a range of approaches to parenting and dealing with unusually bright offspring.

Longyin's dad, Terence, a former Hong Kong policeman, has prepared a terrifying after-school programme for his son – half an hour of PE, one hour's homework, half an hour domestic chores, one hour Chinese, half an hour leisure ... Even the leisure has an educational feel: Terence tests Longyin on world capitals while they play table tennis: it's ping pong geography.

Terence has it all worked out. "You either have a little bit disciplinary life in your first 16 years and then enjoy the remaining 60. Or – choice B – you do whatever you want in the first 16 years and then you become really really depressed, or homeless, for the next 60 years, provided that you are not killed by a drug overdose, gang fighting. So the choice is yours." Yeah, but it's not really Longyin's choice is it Terence? It's yours. I don't imagine much will change when he turns 16 either.

And then there are Hugo's parents, Michelle and Mark, who seem to be ever so slightly embarrassed by the prodigy they've produced, and unsure of how much to encourage him. "Awesome, my favourite waterworks," says Mark, sarcastically, on the train. "He's in the top five percent of ... irritating children," says Michelle, practically rolling her eyes. Michelle hopes that by learning the trumpet, Hugo will join an orchestra and meet girls, "and possibly get a shag out of it". Whoah, not yet Michelle. She does add "when the time comes", to be fair to her. Hugo's got the best parents too.

The tone of the series (there are three parts to come) is about right. Not snarky or sneery, more celebratory but still able to see the funny side: similar to that lovely film Spellbound. I'd like to have seen a few more of the questions, once we got to the competition. For my child, just to see ... No! he's going to be a footballer, it's already decided. Plus he'll get a lot more shags out of that than through playing the bloody trumpet.

Agnetha: Abba and After (BBC1) was fascinating about Abba, less so about After. There's a new project, involving Gary Barlow. Here he is being obsequious. Have the Windsors got bored with him and booted him out, so now he's bothering Swedish pop royalty instead? You're not going to get any more letters after your name from her, Gary. Run along now.